It is known to provide drinking lids for beverage containers such as tumblers and mugs to help maintain the temperature of the beverage within the container and to reduce the spillage of the beverage from the container during use. It is further known to provide such lids with drinking ports that can be selectively opened to allow a user to drink beverage from the container and closed so as to restrict or prevent leakage of the beverage from the container. One known way of providing this function is to provide a stopper or seal for the drinking port that is pivotally mounted to the lid between an open and closed position. Another known solution is to provide a valve on an internal side of the lid that can be selectively actuated by user between an open position and a closed position. One problem with such valves is that they may not have a sufficient amount of open area to provide a desired flow rate of the beverage from the container. One known solution to this problem is to provide a disk-shaped valve head that provides an opening area with a diameter that is slightly smaller than the inside diameter of the container adjacent the valve head. However, one problem associated with such disk-shaped valve heads is that a pressure differential can form across the valve head making it difficult to open. In answer to this problem, it is known to provide a pressure relief valve that can be opened so as to equalize the pressure across the valve head.
While known lid constructions may be suitable for their intended purpose, there is always room for improvement.